The way I go about this usually is to compile such elements in a separate file, creating a PDF file which I can then put into the presentation via \includegraphics. It's especially convenient if you reuse the same illustration made up by several components more than once.
My minimum template example for such a figure file is as follows:
\documentclass[11pt]{article}
\usepackage{tikz}
\usepackage[graphics,tightpage,active]{preview}
\PreviewEnvironment{tikzpicture}
\pagestyle{empty}
\begin{document}
\sffamily
\begin{tikzpicture}
\draw (0,0) circle (2cm);
\end{tikzpicture}
\end{document}
The use of the preview package will crop the PDF to exactly the dimensions of the drawn picture. I am using \sffamily here because it mostly looks better for presentations, but depending on usage it could also be left out.
[shift={(x,y)}]option to the scope. – percusse Jan 16 '13 at 00:07textposnot longer sufficient? This could be related: http://tex.stackexchange.com/questions/85269/easy-absolute-positioning-in-beamer – bloodworks Jan 16 '13 at 09:09